This invention relates to surgical apparatus and methods in general, and more particularly to surgical apparatus and methods for the repair of articular cartilage defects.
Articular cartilage defects have long been a serious problem for patients and orthopedic surgeons. No matter how small the initial defect, it carries with it a high potential for progressing into larger, more symptomatic defects, with the accompanying early arthritis and disabling pain and dysfunction.
Over the years, a number of different procedures have been devised for treating articular cartilage defects.
Articular cartilage defects have traditionally been treated with chondroplasty, shaving, microfracture, abrasion arthroplasty and, most recently, autologous transplantation. Early on, the treatment of articular cartilage defects was principally concerned with preventing a progression of the defect. More recently, attention has been focused on developing ways to actually repair the defect and effect articular cartilage healing.
More particularly, chondroplasty and shaving are principally concerned with removing offending portions of the articular cartilage (e.g., loose flaps, rough edges, etc.) so as to prevent the enlargement of an existing articular cartilage defect. While chondroplasty and shaving have proven helpful in preventing the spread of an existing articular cartilage defect, they do not actually repair the defect or effect articular cartilage healing.
The basic idea behind microfracture and abrasion arthroplasty is to violate the subchondral plate, thereby allowing blood (preferably including marrow cells) to fill the defect and initiate an injury repair. This may be done in a variety of ways well known in the art, e.g., with a rasp to abrade the defect, a pick to pick away the area of the defect, a drill to microdrill the area of the defect, an RF probe (or otherwise) to heat and thereby disrupt the region of the defect, etc. It is known that such a procedure does not actually cause articular cartilage to grow in the defect. Rather, a fibrocartilage/Hyaline cartilage regenerates which, while generally not as good as articular cartilage since it lacks the mechanical properties of the articular cartilage, is certainly better than bare bone. However, a common problem with this technique is that the blood (and marrow) cells do not tend to stay seeded in the defect, since they are commonly wiped away by joint motion and/or other factors.
Autologous cartilage transplant is a potentially attractive alternative for healing articular cartilage defects. This has principally been addressed in two different procedures.
In one procedure, generally referred to as osteocondral grafting, a plug of healthy articular cartilage and underlying bone is harvested from a donor site and transplanted to the defect site. While this technique has proven effective, it typically causes serious damage to the donor site. In addition, it can be difficult to find donor sites with the proper surface profiles, and it can be difficult to properly align the layers (i.e., cartilage and underlying bone) of the graft plug with the layers of the defect site.
In the second procedure, sometimes referred to as autologous cell transplantation, cells from healthy articular cartilage are harvested, multiplied outside the body and then reimplanted at the defect site. This has been accomplished most recently by a system available from Genzyme of Boston, Mass. under the trade name Carticell. However, this system does have its drawbacks: it requires at least two surgical procedures (i.e., one to harvest the cells and one to reimplant them); it is relatively expensive; and there are limits in the size of lesion, and the number of lesions, that can be treated. Also, with this system, the defect generally has to be xe2x80x9ccontainedxe2x80x9d in order for the system to be successful.
Accordingly, one object of the present invention is to provide improved apparatus for the repair of articular cartilage defects, wherein the apparatus can be used with microfracture and abrasion arthroplasty.
Another object of the present invention is to provide an improved method for the repair of articular cartilage defects, wherein the method can be used with microfracture and abrasion arthroplasty.
And another object of the present invention is to provide improved apparatus for the repair of articular cartilage defects, wherein the apparatus can be used with autologous cell transplantation.
Still another object of the present invention is to provide an improved method for the repair of articular cartilage defects, wherein the method can be used with autologous cell transplantation.
These and other objects are addressed by the provision and use of the present invention which, in one form of the invention, comprises an encapsulation device adapted to encapsulate loose-bodied cells (e.g., blood and marrow cells, pluripotent stem cells, autologous cartilage cells, etc.) so as to facilitate the repair of articular cartilage defects. The encapsulation device is preferably formed out of bioabsorbable or bioremodelable materials, such that the encapsulation device will only be present at the surgical site for a limited period of time following surgery.
In another aspect of the present invention, there is provided an encapsulation device for the repair of articular cartilage defects. The device comprises a body for disposition adjacent a bone in an area of the cartilage defect, and elongated leg structure extending from the body for disposition in the bone in the area of the cartilage defect. The leg structure is provided with a length which is a plurality of magnitudes greater than a thickness of the body, and is of a generally conical configuration.
In accordance with a further feature of the invention, there is provided a system for effecting articular cartilage defect repair. The system includes an encapsulation device comprising a body for disposition adjacent a bone in an area of the cartilage defect, and elongated leg structure extending from a distal surface of the body for disposition in the bone in the area of the cartilage defect, wherein the elongated leg structure comprises one or more legs. Each leg of the leg structure is provided with a central opening therein extending from a proximal surface of the body. A pilot hole device is provided comprising a head portion, at least one elongated foot extending distally from the head portion, and a handle portion extending proximally from the head portion, the pilot hole device elongated foot being adapted to form a pilot hole in the bone to receive a leg member of the leg structure. An insertion tool is provided comprising a head portion, at least one elongated foot extending from a distal end of the head portion, each elongated foot of the insertion tool head portion being adapted to be received by the central opening of one of the encapsulation device legs. The insertion tool head portion is adapted to engage a proximal surface of the encapsulation device. The encapsulation device is adapted to be mounted on the insertion tool, and the insertion tool may be manipulated to drive the encapsulation device leg structure into at least one hole in the bone, to place the encapsulation device distal surface adjacent the bone and in the area of the cartilage defect.
In accordance with a still further feature of the invention, there is provided a tool for in-bone placement of an encapsulation device for repair of an articular cartilage defect, the device comprising a body portion and a cannulated leg extending distally from a center of a distal surface of the body portion. The tool comprises a head portion having a distal surface configured generally complementary to a proximal surface of the encapsulation device, a handle portion extending proximally from the head portion, the head portion and handle portion forming a bore extending axially of the head portion and handle portion, and an insertion spike extending through the bore and adapted to extend through the encapsulation device leg, with a pointed distal end of the spike extending distally from a distal end of the encapsulation device leg. The insertion spike is adapted to form a hole in the bone and the tool is adapted to push the encapsulation device leg into the hole and the encapsulation device body into engagement with the bone.
In accordance with a still further feature of the invention, there is provided a method for effecting a repair to an articular cartilage defect. The method includes the steps of providing an encapsulation device comprising a body for disposition adjacent a bone in an area of the cartilage defect, and an elongated leg structure extending from the body for disposition in the bone in the area of the cartilage defect, wherein the elongated leg structure comprises at least one leg, producing a hole in the bone for each leg of the encapsulation device leg structure, and driving each leg of the leg structure of the encapsulation device into a hole in the bone to bring a distal surface of the encapsulation device body into adjacency with the bone.
The above features of the invention, including various novel details of construction and combinations of parts and method steps, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular devices and methods embodying the invention are shown by way of illustration only and not as limitations of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.